Influence of Blank-Holder Force on Springback of Cap-Shape Parts Bending

Springback is the prominent problem in bending forming of sheet metal, which is difficult to control accurately, especially for the complex shaped bending parts. The change of blank-holder force will cause significant changes of bending springback amount. The theoretical analytical model of cap-shape parts bending, which takes into account of the harden ability, anisotropy and elastic deformation of material, is proposed in this paper based on the plane deformation assumption and the bending theory of sheet metal, the cap-shape parts bending of wide sheet is analyzed theoretically, the approximate calculation relational expression is derived between the blank-holder force and springback angle, and the influence of blank-holder force on springback is discussed. In the same conditions, the springback result deduced from theoretical formula is basically consistent with numerical simulation and experiment result.

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Influence of Friction on Springback of Quadrangle Parts Bending

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.217-218.619 ◽

2011 ◽

Vol 217-218 ◽

pp. 619-624

Author(s):

Chun Jian Su ◽

Guang Heng Zhang ◽

Su Min Guo ◽

Li Gao ◽

Rui Ma

Keyword(s):

Numerical Simulation ◽

Friction Coefficient ◽

Sheet Metal ◽

Analytical Model ◽

Elastic Deformation ◽

Approximate Calculation ◽

Plane Deformation ◽

Theoretical Formula ◽

Simulation And Experiment ◽

Springback Angle

Springback is the prominent problem in bending forming of sheet metal, which is difficult to control accurately, especially for the complex shaped bending parts. The change of friction conditions will cause significant changes of bending springback amount. The theoretical analytical model of quadrangle parts bending, which takes into account of the harden ability, anisotropy and elastic deformation of material, is proposed in this paper based on the plane deformation assumption and the bending theory of sheet metal, the quadrangle parts bending of wide sheet is analyzed theoretically, the approximate calculation relational expression is derived between friction coefficient and springback angle, and the influence of friction on springback is discussed. In the same conditions, the springback result deduced from theoretical formula is basically consistent with numerical simulation and experiment result.

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Numerical Simulation Research on Springback Controlling Methods of Aluminum Alloy Panel during Hydroforming

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.851.163 ◽

2016 ◽

Vol 851 ◽

pp. 163-167

Author(s):

Dong Yan Lin ◽

Yi Li

Keyword(s):

Numerical Simulation ◽

Aluminum Alloy ◽

Process Parameters ◽

Orthogonal Experiment ◽

Blank Holder Force ◽

Scoring Method ◽

Simulation Research ◽

Blank Holder ◽

Hydroforming Process

The hydroforming process of the aluminum alloy panel was simulated by the software DYNAFORM. The effects of process parameters (blank holder force, depth of panel and height of draw bead) on springback of the aluminum alloy were investigated. The max springback of the panel was analyzed by weighted scoring method. Then the process parameters were synthetically optimized for the max positive and negative springback. The results showed that the height of draw bead affects obviously the comprehensive springback of the panel. The optimization of the process parameters obtained by the orthogonal experiment can effectively reduce the max springback of the panel.

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Applying 2k Factorial Design to Study on Parameters Affecting Springback of Forming of Advanced High Strength Steel Sheets (AHSS)

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.872.83 ◽

2017 ◽

Vol 872 ◽

pp. 83-88

Author(s):

Ramil Kesvarakul ◽

Chamaporn Chianrabutra ◽

Watcharapong Sirigool

Keyword(s):

Elastic Recovery ◽

Weight Ratio ◽

High Strength ◽

Die Design ◽

Statistical Experimental Design ◽

Blank Holder Force ◽

Forming Process ◽

Blank Holder ◽

Punch Radius ◽

Springback Angle

Advanced high strength steels (AHSS) are widely used in the automotive industry due to their appropriate strength to weight ratio. This alloy has unique hardening behavior and variable unloading elastic modulus; however, the unavoidable obstacle of AHSS sheet metal forming is springback. The springback is a result of elastic recovery and residual stress. The aim of this study is to determine the proper process parameters enabling the reduction of the springback defects in AHSS forming process. This work was divided into two parts, regarding to the effects of numerical parameters and process parameter on forming AHSS. In this paper, a U-shape forming was used to examine the springback behaviors, such as springback angle, sidewall curl, and thickness, through an experiment. To achieve this purpose, 2k factorial statistical experimental design has been employed to investigate the parameters affecting the springback of forming in AHSS to find out the main effect in the springback reduction focusing on using as a guideline for die design. It showed that the blank holder force is the most influential parameter. The second is the punch radius. However, the blank holder force and punch radius is not simple to adjust in die design, the die radius becomes the important parameter to be used to reduce the springback angle.

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Study of the Parameters of Deep Drawing Process Based on the Simulation of Dynaform

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.249-250.51 ◽

2012 ◽

Vol 249-250 ◽

pp. 51-58

Author(s):

Qing Wen Qu ◽

Tian Ke Sun ◽

Shao Qing Wang ◽

Hong Juan Yu ◽

Fang Li

Keyword(s):

Friction Coefficient ◽

Sheet Metal ◽

Deep Drawing ◽

Drawing Process ◽

Blank Holder Force ◽

Blank Holder ◽

Deep Drawing Process ◽

Drawing Die ◽

Drawing Speed

A simulation of deep drawing process on the sheet metal was done by using Dynaform, the influence of blank holder force, deep drawing speed and friction coefficient on the forming speed of sheet metal in the deep drawing process were got. The forming speed of sheet metal determines the quality of deep drawing, in the deep drawing process the blank holder force and the deep drawing speed are controllable parameters, the friction coefficient can be intervened and controlled, and it’s a manifestation of the interaction of all parameters, the main factors which influence the friction coefficient just have blank holder force, deep drawing speed and lubrication except the material. The conclusion of this study provides the basic data for the analysis of the lubrication of mould, the study of lubricant and the prediction of the service life of deep drawing die.

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Optimization of Process Parameters of U-Shape Sheet Metal Based on Compensation of Geometric Springback Value

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.455-456.1122 ◽

2012 ◽

Vol 455-456 ◽

pp. 1122-1127

Author(s):

Xiang Wu Jia ◽

Shu Gen Hu

Keyword(s):

Sheet Metal ◽

Process Parameters ◽

New Method ◽

Blank Holder Force ◽

Technological Parameters ◽

Blank Holder ◽

Optimization Of Process Parameters

Taking example for U-shape sheet metal, the paper studies the forming and springback process with Dynaform, how much the springback influenced by several factors is studied, including die figure, stamping velocity, the stroke, the blank holder force and friction. Then a useful conclusion can be reached: Using die figure to optimize the technological parameters remarkably reduce the springback value, it provides a new method to control and solve the springback issue.

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Numerical Simulation of Deep-Drawing Processes of Square Cup under Bilateral Constrained Conditions

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.2892 ◽

2011 ◽

Vol 189-193 ◽

pp. 2892-2896 ◽

Cited By ~ 2

Author(s):

Xiao Ting Xiao ◽

Li Cheng Huang ◽

Yi Juan Liao ◽

Li Guang Tan ◽

Qiao Yu Chen

Keyword(s):

Numerical Simulation ◽

Friction Coefficient ◽

Deep Drawing ◽

Material Flow ◽

Flow Rule ◽

Blank Holder Force ◽

Analysis Software ◽

Blank Holder ◽

Advanced Analysis ◽

Constrained Conditions

In this paper, the flow rule of metal during the deep drawing of the non-symmetry workpieces was investigated by means of the numerical simulation of deep-drawing processes of square cup under bilateral constrained conditions. The numerical simulation was carried out by advanced analysis software Dynaform5.5. SUS304 stainless steel was used as the deforming materials. The influence of different friction coefficient and blank holder force on the drawing forming quality was analyzed. The results showed that the material flow in different areas has different trends with increase of friction coefficient and blank holder force.

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The Computation and Measurement of Residual Stresses in Laser Deposited Layers

Journal of Engineering Materials and Technology ◽

10.1115/1.1584493 ◽

2003 ◽

Vol 125 (3) ◽

pp. 302-308 ◽

Cited By ~ 22

Author(s):

S. Finnie ◽

W. Cheng ◽

I. Finnie ◽

J. M. Drezet ◽

M. Gremaud

Keyword(s):

Numerical Simulation ◽

Stress Distribution ◽

Residual Stresses ◽

Metal Forming ◽

Steel Substrate ◽

Plane Deformation ◽

Compressive Stresses ◽

Out Of Plane ◽

Simulation And Experiment ◽

Melted Material

Laser metal forming is an attractive process for rapid prototyping or the rebuilding of worn parts. However, large tensile stress may arise in layers deposited by laser melting of powder. A potential solution is to preheat the substrate before and during deposition of layers to introduce sufficient contraction during cooling in the substrate to modify the residual stress distribution in the deposited layers. To demonstrate the value of this approach, specimens were prepared by depositing stellite F on a stainless steel substrate with and without preheating. Residual stresses were computed by numerical simulation and measured using the crack compliance method. For non-preheated specimens simulation and experiment agreed well and showed that extremely high residual tensile stresses were present in the laser melted material. By contrast, pre-heated specimens show high compressive stresses in the clad material. However, in this case the numerical simulation and experimental measurement showed very different stress distribution. This is attributed to out of plane deformation due to the high compressive stresses which are not permitted in the numerical simulation. A “strength of materials” analysis of the effect of out of plane deformation was used to correct the simulation, Agreement with experimental results was then satisfactory.

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